Diametrically (used in the figurative sense)
One of my favorite vocabulary acquisitions is “defenestrate” - having studied the French language for many a moon, I had a good idea of the meaning, but now that I’ve read a definition for the term it’s proved most useful in meetings, e.g.:
“If John would be so kind as to allow me to defenestrate his point…” Folks not paying attention assume you mean “demonstrate”, and with the consenting nods you’re granted permission to throw something out the window. Can’t beat it! 
My fav is penultimate. It means next to the last. I first heard it in an old silly song called Have some Madeira, m’dear
I’m also partial to plethora, and flummoxed. I use trice occasionally
START priapic means phallic, from the Roman God, Priapus. The god of male sexual power.
Wikkit You mean methylethylkillyounow chemicals? :eek:
b_anthracis"fenestrate" is used in medicine it means to make a hole into something.
Not the latest I have learned, but the last really cool one.
I’m on the “Word-a-Day” emial list as well. My favorite so far:
Scrofulous.
Don’t have the word-a-day def any more, but according to Webster’s:
Main Entry: scrof·u·lous
Pronunciation: -l&s
Function: adjective
1 : of, relating to, or affected with scrofula
2 a : having a diseased run-down appearance b : morally contaminated
Definition 2 fits my boss perfectly, especially with the add-on “fool”. He’s a scrofulous fool.
Kinda melts in your mouth, doesn’t it?
To use the spoiler tag, type it with brackets like this [ spoiler ] and [ /spoiler ] (without the spaces, of course)
I like the word ubiquitous. It just has a nice ring to it.
I didn’t know about m-w’s word of the day. I just signed up.
I’ve always thought that defenestrate is the wrong word for throwing something out of a window - it should perhaps be exfenestrate. Defenestrate should be the removal of a window, c.f. declaw, declassify, derail etc. But I guess it’s not going to change.
I find “sesquipedalian” amusing because it’s autological, ie. describes itself. Other autological words include “short”, “English”, and, in my opinion “euphonius”. The opposite is “heterological”, words which don’t, for instance, “long”, “Anglais”, “table” and “however”. Pop quiz: what word in the english language is neither autological nor heterlogical. 
Heterological, perhaps?
Never heard that one, thanks.
Ooh, that’s a good one, I’ll have to remember that. I used to work with methylethylketone, aka MEK, and it was nasty stuff.
1,1,1,2-tetrafluoroethane is the stuff in canned “air”, and sodium hexametaphosphate is used for soil dispersion and as a food additive (like in fake lemonade). Not that anyone was curious.
widdershins (counterclockwise)
deosil (clockwise)